U.S. Pat. No. 4,259,373, Demessemaekers et al., issued Mar. 31, 1981, assigned to the owners of the present invention, discloses a method of conditioning fabrics in which a granular solid fabric conditioning material is enclosed in an envelope with a porous wall communicating between the granular composition and the water of a washing machine. This is sometimes a preferred delivery system for fabric softeners for reasons disclosed in that application.
However, some fabric softening compositions are not efficiently delivered to a laundry rinsing liquor using this and other delivery systems, for the reason that certain softening materials, particularly those in a solid, granular form, are not easily dispersed in the rinsing liquor. This problem is especially prominent when cold water is used in the washing machine rinse cycle during which softening is to take place. (The rinse cycle is the preferred stage at which the softener should be transferred to the fabrics.) Since the cost of energy has increased enormously in recent years, it is now very important to provide fabric conditioning compositions which will work well in a cold rinse. An improvement in the dispersibility of granular fabric softeners in cold water is required if the need to reduce the energy cost of laundering is to be met.
Several patents state or suggest that certain quaternary ammonium compounds which are very useful in the softening of fabrics are not easily dispersed in the rinse water of a washing machine. U.S. Pat. No. 3,356,526, issued to Waldman et al., on Dec. 5, 1967, and U.S. Pat. No. 3,573,091, issued to Waldman et al. on Mar. 30, 1971, each disclose the use of powdered carriers to render quaternary compounds water dispersible; the '526 reference teaches the practice of that invention using the chloride analog of ditallow dimethyl ammonium methyl sulfate. U.S. Pat. No. 3,892,669, issued to Rapisarda et al. on July 1, 1975, and U.S. Pat. No. 3,325,404, issued to Cohen et al. on June 13, 1967, each disclose solubilizing agents which may be combined with ditallow dimethyl ammonium methyl sulfate or other di-(short chain), di-(long chain) quaternary ammonium compounds in order to solubilize these compounds in aqueous liquid fabric softening compositions.
The following references disclose liquid fabric softening compositions which contain mixtures of softening ingredients relevant to the present invention: U.S. Pat. No. 3,349,033, issued to Zuccarelli on Oct. 24, 1967, discloses a liquid fabric softening composition which may contain 6% of a softening agent which may be, for example, ditallow dimethyl ammonium methyl sulfate and 2% of a microbiological control agent which may be, for example, dodecyl or hexadecyl trimethyl ammonium chloride. U.S. Pat. No. 3,904,533, issued to Neiditch et al. on Sept. 9, 1975, discloses a liquid fabric softener which may contain, for example, ditallow dimethyl ammonium methyl sulfate (or one of many other homologs thereof) in combination with myristyl trimethyl ammonium bromide (or one of many other homologs thereof) as a low temperature stabilizing agent. U.S. Pat. No. 3,329,609, issued to Blomfield on July 4, 1967, teaches a composition of 20% to 80% of a generic material which includes ditallow dimethyl ammonium methyl sulfate in its definition; 5% to 10% of a material which may be myristyl trimethyl ammonium bromide; and 80% to 20% of a salt of hydrofluorosilicic acid. In Col. 4 this reference indicates that a large quantity of inert filler material may be added to the composition, and further indicates that the composition may be blended together in the form of dry ingredients. The overall suggestion of this reference is that the composition is a solid material.